In semiconductor substrate processing, the temperature of the substrate is often a critical process parameter. Changes in temperature, and temperature gradients across the substrate surface during processing are often detrimental to material deposition, etch rate, feature taper angles, step coverage, and the like. It is often desirable to have control over a substrate temperature profile before, during, and after substrate processing to enhance processing and minimize undesirable characteristics and/or defects.
The substrate is often supported upon a substrate support or pedestal having a centrally located support shaft to support the substrate support. The substrate support often includes one or more embedded heaters adapted to heat a substrate disposed thereon. However, the inventors have observed that conventional heated substrate supports with embedded heaters often display a temperature non-uniformity at the central region of the substrate support resulting in non-uniform of process results in the substrate. The inventors have observed that, in some cases, the temperature non-uniformity of the substrate support can be attributed to the support shaft drawing heat away from the substrate support.
Therefore, the inventors have provided embodiments of a heated substrate support having improved temperature uniformity.